Air conditioning system



Dec. 22, 1953 J. D. STROBELL AIR CONDITIONING SYSTEM 2 Sheets-Sheet 1 Filed 001;. 4, 1949 INVENTQR E m m Mm Dec. 22, 1953 J. D. STROBELL FIG. 2.

2 Sheets-Sheet 2 l I" 00' 9; x03

BY 6%.; HEM

ATTORNEYS Patented Dec. 22, 1953 TNT ()FFICE AIR CONDITIONING SY STEM John D. Strobell, New Haven, Conn.,assignor to The Safety Car Heating and Lighting Company, I nc., New Haven,- Conn., a corporation of. Delaware Application October 4, 1949, Serial No. 119,505

' 12 Claims. (01. ac-3) This invention relates to an air-conditioning system of the steam ejector type and more particularly to a vacuum-operated valve employed in such a system to control its operation under predetermined conditions. The system is especially adapted for use in railroad cars where a large amount of steam is readily available.

An object of this invention is to provide a.

system for air conditioning an enclosurev which is simple and rugged in construction and emcient in operation. Another objectis to provide a system of the above character which employs a minimum number of moving parts and consequently requires a minimum amount of servicing and repair. A further object is to provide a system of the above character including a control valve operatively responsive to certain desired conditions in the system. Stillanother object is to provide a system of the above character employing electrical controls which are free from complications. Other objects will be in part apparent and in part pointed-out hereinafter.

The invention, accordingly consists in the features of construction, combination of elements andarrangement of parts as will be exemplified in the structure to be hereinafter described, and the scope of the application of which'will be indicated in the following claims.

In the drawings:

Figure l is a diagrammatic representation of the'system;

Figure 2 is an enlarged sectional view illustrating in detail one of the valves shown in Figure 1; and I Figure 3 is a sectional view illustrating in detail another valve shown in Figure l. 7

Similar reference characters refer to similar parts throughout the several views of the drawings.

Air conditioning systems of the steam ejector type are employed in railroad cars because of the availability of steam under high pressure. In these systems, thesteam is directed through a venturi device connected to an evaporating chamber, after which it passes to a condenser. This creates a partial vacuum in the evaporating chamber to increase evaporation of water sprayed therein, resulting in cooling of the water. The water is used to cool an enclosure such as a railroad car.

Sincethe above system is generally employed on railroad. cars, it has to operate for long periods. of time without servicing and therefore rugged equipment is desirable. Obviously, the

system must be accurately controlled to prevent damaging the. parts. For example, pressure conditions in the condenser must be such as to assure proper condensation of the steam during operation. Thus a-suitable valving mechanism is provided to control steam flow according to condenser pressure conditions. Accordingly, steam flow is not permitted until the condenser is in operating condition whether or not the ther mostat is calling for cooling.

The air conditioning system shown in, Figure 1 has a venturi device, generally indicated at H), a condenser, generally indicated at [2, :and an evaporator, generally indicated at M. Thesventuri device [0 includes a nozzle I6 which directs the steam into the constricted portion l8 of the venturi to draw a partial vacuum on evaporator l4 through connection I5 between the lower end of venturi l0 and the evaporator. The other end of venturi, I0 is connected by a header 20 to condenser l2. The other end of they condenser is connected by a header 24 to a pipe .26 leading to a trap 23.

To condense the steam passing through the venturi device t0, the condenser is cooled by water sprayed upon pipes 22 by anozzle 46a at the end of pipe 46. Such water is drawn from a sump 25-by a pump 48 driven by a motor 50, and pumped through pipe 44, purge ejector 45 and pipe 46 to nozzle 46a.- The water sprayed upon condenser '22 falls downwardly to the bottom of enclosure 93, from which it drains tov sump 25 through pipe 27'. Air for cooling condenser 22 is circulated through enclosure 23 by a fan 52, the air entering the enclosure 23 through opening 54 and leaving through opening 56.

Condensation flowsfrom the condenser through pipe 26 to trap 23, from which excess water is drawn by means of purge ejector 45 which is connected to trap 23 by pipe 29. Purge ejector 45 also draws a partial vacuum on condenser I2 through pipe for purposes to be disclosed more fully hereinafter.

. Water, cooled by evaporation in a manner to be described, is circulated between the evaporator and cooling coil 34 in the interior of the car 30 by pump 32. During cooling, air is forced over pipes 34 and through the car by a suitable fan (not shown). More particularly, the water flows from the. evaporator l4 through pipes 36 and 38, and, after circulating through the coil 34, returns through pipe 42 to the evaporator l4, where it is sprayed downwardly through small holes 42a in the pipe.

A valve, generally indicated at 58, controls the flow of .steam to the nozzle [6. When the valve is open, steam flows from a source (not shown) through pipes 59 and 52 to the nozzle it. The action of the venturi device produces a suction on the evaporator, resulting in a partial vacuum therein. Water in the evaporator falling from the pipe 42 through this partially evacuated space evaporates rapidly, resulting in effective cooling thereof.

To maintain a constant level of water in evaporator i4, evaporator I4 is connected to trap 23 by a pipe 3|. Flow of water through pipe 31 into evaporator I4 is controlled by a float valve, generally indicated at 33. When the water in the evaporator falls below a certain level, valve 33 opens and water flows from trap 23 into evaporator M until the evaporator again contains the required amount of water.

For effective operation to cool the coil 34 there must be an adequate source of steam to assure proper operation of the Venturi device and the consequent desired partial vacuum condition in the evaporator. To the same end, the condenser must operate properly and such operation is dependent on the maintenance of a proper pressure condition therein. The availability of adequate steam under pressure and proper condenser conditions are therefore made a prime requisite of a cooling operation of the system even though the car thermostat is calling for cooling.

Accordingly, the operation of the valve 58 is dependent upon several conditions in the system: (1) a thermostatic switch 40 in the car 39 must call for cooling by closing, (2) a pressure-responsive switch 64 in the steam line 59 must close, indicating a source of steam under sufficient pressure, and (3) valve 58 responsive to condenser pressure conditions must open, indicating a satisfactory condenser condition. The present system includes apparatus whereby the operation of the system is dependent upon all of these conditions.

Valve 58 is shown in detail in Figure 2, wherein the valve body, generally indicated at 895, is connected to pipes 69 and 62 and is provided with a valve seat '16. A fitting 14 forming a portion of the valve is threaded into valve body I and includes an outwardly extending annular flange 14a. The upper portion of a cylindrical casing fits about and is supported upon flange portion l'fla by an inwardly extending integral flanged portion 15a. Fitting 14 is provided with a vertically extending bore H within which fits a sleeve 18. Within the sleeve 18 is a valve stem 19 having a flange 89 formed on its lower end and a valve head 8! at its upper end coacting with the valve seat 16. Stem 19 is threaded into a spring seat 82 at its lower end secured to the central portion of a bellows 83. The upper periphery of bellows 83 forms an air-tight connection with the undersurface of annular flange Ma. Bellows 83 is expansible in vertical directions within the cylindrical casing 15 and a vent 89 to the atmosphere is provided in flange 14a leading into the interior of bellows 83 so that the interior of the bellows is open to atmospheric pressure at all times.

To prevent steam from passing through the opening Mb and thence into the interior of bellows 83, a flexible tubular sealing device 99 is secured to the fitting l4 and flange 99 and is positioned within sleeve 18. Sealing device 90 is expansible to permit the valve stem l9 to move freely upwardly and downwardly and at all times effectively seals the interior of bellows 83 from the pressures existing in pipe 59. Thus, the interior of bellows 83 is maintained at atmospheric pressure at all times. The area of valve head BI is equal to the effective area of the interior of bellows sealing device 90 and thus steam under pressure passing through opening Nb and acting on the interior of bellows 9|] is counterbalanced by the steam pressure acting on valve head 8|.

A downwardly extending centrally located tubular extension 84 of casing '55 has a cap member 95 threaded on its lower end and a spring seat 89 slidably supported within tubular portion 8:2 upon an adjusting screw 81 threaded in cap 95. A spring 88 is supported between spring seats 32 and 85, the spring seat 82 having an annular depending flange 82a. for supporting the spring in this position. Accordingly, it will be seen that by adjusting screw 91, any desired pressure may be exerted on the bottom of bellows 83 by way of compression of the spring 88. Spring 99 is preferably set so that atmospheric pressure within bellows 83 will move valve head 8| downwardly when the pressure within space 9| is of twenty inches vacuum or less. Valve head BI moves into engagement with seat 19 when the pressure within space 9| is above ten inches vacuum.

The solenoid valve, generally indicated at 68 in Figure 1, is shown in detail in Figure 3. The armature 92 of the solenoid 93 is connected to a valve stem 95 having a valve head 95. The support 96 for the solenoid 93 has a fitting 91 threaded therein with a vertically extending bore 98. A spring 99 fits within bore 98 to urge the valve head 95, downwardly away from a valve seat 599 formed in a centrally located chamber IUI in fitting 91'. A vent I92 to the atmosphere extends into the bore 98 so that when solenoid 93 is deenergized, the chamber l9i is connected to the atmosphere, spring 98 holding valve head 95 against a seat I93. When solenoid 93 is energized, valve head 95 is moved upwardly into engagement with seat I09, cutting ofi vent Hi2 from chamber llil.

Referring to Figures 1 and 3, pipe 96 is connected to chamber l9l of valve 68 as is pipe 13. Thus, when valve head 95 is seated on seat I09, pipes 96 and it connect the pressure existing in the condenser head 24 with the space 9| in casing 15 of valve 53, as seen in Figure 2, and when valve head 95 is seated on seat I03, space 9| is connected to the atmosphere.

To prevent solenoid valve 68 from connecting pipe 66 to pipe 13 until a partial vacuum has been drawn on condenser l2 by purge ejector 45, a condenser pressure switch 69 is positioned in the circuit of solenoid 93. This switch is connected by a pipe 6! to a pipe 66, which is connected to condenser l2 by a pipe 65. When the pressure in pipe 66 is twenty inches vacuum or less, switch 59 closes, completing the circuit to solenoid 93. This causes valve 58 to open, connecting space 9! in valve 58 to the condenser. Because of the differences in pressure at this time between the partial vacuum in space 9| and the atmospheric pressure in bellows 83, valve 8| snaps into an open position.

In operation, when thermostatic switch 49 is closed, calling for cooling, and pressure responsive switch 64 closes, indicating that the pressure of the supply steam is above a minimum value, the circuit to motor 59 is completed. Water flowing through pipe 44, purge ejector and pipe 49 to nozzle 36a acts through purge ejector p p 29 and p p to draw a partial vacuum terior of bellows 83 (Figure 2) compresses spring 88 and snaps valve 81 open. Steam then flows past valve seat It to nozzle 16 (Figure 1) drawing a vacuum on evaporator I l. The water within evaporator it is circulated by pump 32 through coil 34 and then back into the evaporator through pipe 42.

When either switch 4% or switch 64 opens, the

circuit to the solenoid 0.5 valve 68 (Figure 3) is broken. Spring 58' then moves valve head S downwardly against valve seat I93, cutting off. the connection between. condenser it (Figure l) and space 9! (Figure 2) in valve 53 and connecting space 9! to atmospheric pressure through vent [82. Spring 88 then moves valve head 8i upwardly, preventing further flow of steam to nozzle l6 (Figure 1) 'At the same time, the circuit to motor 5c is broken, stopping the operation of spray pump 43. operation of the machine, and it, in turn, is controlled by switches 40 and 5:1 and the pressure within condenser 12. If either switch 40 or as opens, or if the condenser pressure is above ten inches vacuum, then valve head 81- (Figure 2) shuts oil the flow of steam to the nozzle I6 (Figure 1). On the other hand, the only time that the steam valve 58 opens is when both switches Gil and 6 3 are closedand the condenser pressure is less than twenty inches vacuum. Thus, a practical and eilicient air-conditioning system has been disclosed. which is controlled by a vacuumoperated valve in an eflicient and practical manner. Itwill thus be seenthat the several objects hereinabove mentioned, as well as many others, have. been successfully accomplished As many possible embodiments may be made of the above invention, and as 'many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as. illustrative andnot in a limiting sense.

What is claimed is:

1. In a control for 'a steam ejector air-conditioning system including a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to saidejector, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a pressure responsive valve'controlling the flow of steam through said pipe, means forming a pressure conducting connection between said condenser and said valve, for controlling the position of said valve by the pressure in said condenser, means for disconnecting said connection, and means operatively connecting said lastmentioned means to said thermostat, said thermostat controlling the operation of said disconnecting means and thus the operation-of said valve.

2. In a control for a steam ejector air-conditioning system including a thermostat, an evapo- This com- Thus, the valve 53 controls the l rator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure line connected to said ejector a. steam pressure responsive elec-- trical switch in said steam pressure line, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a pressure responsive valve controlling the flow of steam through said pipe, means forming a pressure conducting connection between said condenser and said valve for controlling the position of said valve by the pressure in said condenser, means for disconnecting said last-mentioned connection, and means operatively connecting said last-mentioned means to said thermostatand said steam pressure switch, whereby said steam pressure switch and said thermostat control the operation of said disconnecting means and thus regulate the operation of said valve.

3. Ina control for a steam ejector air-conditioning system including a coolant, a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to said ejector, a condenser, and means for drawing a partial vacuum. on said condenser at the start of a cycle of operation, in combination, a pressure operated valve positioned in said steam pressure pipe forcontrolling the flow of steam through said pipe, a pipe forming a connection between the interior of said condenser and said valve, a valve positioned in saidv lastmentioned pipe, and means operatively connecting said last-mentioned valve to said thermostat, whereby said thermostat controls the operation of said last-mentioned valve and thus regulates the operation of said first-mentioned valve.

4. In a control for a steam ejector air-conditioning systemv including a coolant, a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a, steam pressure pipe connected to said ejector, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a control valve positioned in said steam pressure. pipe for controlling the flowof steam therethrough, apipe connecting the interior of said condenser to said control valve, an. electrically-controlled valve positioned in said last-mentioned pipe, said last-mentioned valve closing when the circuit thereto is broken, and a-circuit connecting said last-mentioned valve, said steam pressure switch and said thermostat inseries. V

5, In a control for asteam ejector air-conditicning system including a coolant, a thermostat,

an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on evapcrator, a steam pressure pipe. connected to said eiector.accnde-nser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a pressure responsive control valve positioned in said steam pressurepig, for controlling th flow of steam therethrough, a second pipe connecting the interior cf said condenser to said'prcssure responsive control valve, steam pressure responsiveelectrlcal switch positioned in said steam pressure pipe, an electrically-controlled valve positioned in said second pipe, said last-mew tioned valve closing vhen the circuit thereto is broken, a condenser Pressure switch responsive to pressure in said second pipe, a circuit connecting said last-mentioned valve, said steam pressure switch, said condenser pressure switch and said thermostat in series, whereby if either said thermostat, said condenser pressure switch or said steam pressure switch opens said electricallycontrolled valve will disconnect said condenser from said control valve to interrupt the flow of steam to said ejector.

6. In a steam ejector air-conditioning system, in combination, a thermostat, a steam pressure pipe, a steam ejector, said steam pressure pipe being connected to the nozzle of said steam ejector, a condenser, means for drawing a partial vacuum on said condenser at the start of a cycle of operation, an evaporator, said steam ejector drawing a partial vacuum on said evaporator, a cooling coil, means for circulating a liquid from said evaporator through said cooling coil and thence back into said evaporator, a steam pressure switch operatively connected to said steam pressure pipe, said steam pressure switch opening when the steam pressure in said steam pipe falls below a minimum value, a pressure-operated control valve positioned in said steam pipe, 2. second pipe connecting the interior of said condenser to said control valve, the pressure in said condenser controlling the operation of said valve, and valve means positioned in said second pipe, said valve means closing when said steam pressure switch or said thermostat opens, whereby said control valve is controlled by the pressure in said condenser, said steam pressure switch and said thermostat.

'7. In a steam ejector air-conditioning system, in combination, a thermostat, a steam pressure pipe, a steam ejector, said steam pressure pipe being connected to the nozzle of said steam ejector, a condenser, means for drawing a partial vacuum on said condenser at the start of a cycle of operation, an evaporator, said steam ejector drawing a partial vacuum on said evaporator, a cooling coil, means for circulating a liquid from said evaporator through said cooling coil and thence back into said evaporator, a steam pressure switch operatively connected to said steam pressure pipe, said steam pressure switch opening when the steam pressure in said steam pipe .falls below a minimum value, a pressure-operated main control valve positioned in said steam pipe, a second pipe connecting the interior of said condenser to said control valve, the pressure in said condenser controlling the operation of said valve, further valve means positioned in said second pipe, said further valve means closing when said steam pressure switch or said thermostat opens, and condenser pressure responsive control means operatively connected to said second pipe and to said further valve, said control means preventing said further valve from opening until a partial vacuum is drawn on operation of said main condenser, whereby said control valve is determined by vacuum in said condenser, pressure in said steam pipe and closure of said thermostat.

8. In a control for a steam ejector air-conditioning system including a coolant, a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to said ejector, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a steam pressure responsive switch in said steam pressure pipe, a valve positioned in said steam pressure pipe, said valve including a valve head controlling the flow of steam through said steam pressure pipe, a bellows operatively connected to said valve head, means connecting one side of said bellows to atmospheric pressure, pipe means connecting the opposite side of said bellows to the interior of said condenser, said valve being operated by the difference between the pressure in said condenser and atmospheric pressure, a valve positioned in said pipe means, and means operatively connecting said last-mentioned valve to said thermostat and said steam pressure switch, said last-mentioned valve closing whenever said thermostat or said steam pressure switch opens.

9. In a control for a steam ejector air-conditioning system including a coolant, a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to said ejector, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a steam pressure switch, a valve positioned in said steam pressure pipe, said valve including a valve head controlling the fiOW of steam through said steam pressure pipe, a bellows operatively connected to said valve head, means connecting one side of said bellows to atmospheric pressure, pipe means connecting the opposite side of said bellows to the interior of said condenser, said valve being operated by the difference between the pressure in said condenser and atmospheric pressure, a valve positioned in said pipe means, means operatively connecting said last-mentioned valve to said thermostat and said steam pressure switch, said last-mentioned valve closing whenever said thermostat or said steam pressure switch opens, and pressure con trolled means operatively connected to said lastmentioned valve and to said condenser, said pressure-operated means preventing said last-mentioned valve from opening until a partial vacuum is drawn on said condenser.

10. In a control for a steam ejector air-conditioning system, including a thermostatic switch, a steam pressure switch, an evaporator, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe for supplying steam under pressure to said steam ejector, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a valve positioned in said steam pressure pipe, said valve including a valve head controlling the flow of steam through said steam pressure pipe, a bellows operatively connected to said valve head, means connecting one side of said bellows to atmospheric pressure, pipe means connecting the opposite side of said bellows to the interior of said condenser, said valve being operated by the difference between the pressure in said condenser and atmospheric pressure, a valve positioned in said pipe means, said valve including a pair of ports and a vent to the atmosphere, one of said ports being connected to the portion of said pipe means leading to said condenser and the other of said ports being connected to the portion of said pipe means leading to said first-mentioned valve, a valve head positioned in said second-mentioned valve, and means operatively connecting said second mentioned valve to said thermostatic switch and said steam pressure switch, said thermostatic switch and said steam pressure switch controlling the position of the valve head of said secondmentioned valve, said second-mentioned valve closing Whenever said thermostatic switch or said steam pressure switch opens to disconnect the portion of said pipe means leading from said second-mentioned valve to said first-mentioned valve from said condenser and to connect it to,

coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to said ejector, a steam pressure switch in said steam pressure pipe, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in combination, a bellows-operated valve positioned in said steam pressure pipe, a vent in said valve connecting the interior of said bellows to atmospheric pressure, a casing surrounding said bellows, a pipe connecting the space between said casing and said bellows to said condenser, a second valve positioned in said lasbmentioned pipe, said second valve being operatively connected to and controlled by said thermostatic switch and said steam pressure switch, said second valve disconnecting said condenser from said first-mentioned valve whenever said steam pressure switch or said thermostatic switch opens.

12. In a control for a steam ejector air-conditioning system including a coolant, a thermostat, an evaporator, means for circulating the coolant, a steam ejector for drawing a partial vacuum on said evaporator, a steam pressure pipe connected to said ejector, a steam pressure switch on said steam pressure pipe, a condenser, and means for drawing a partial vacuum on said condenser at the start of a cycle of operation, in

in said steam pressure pipe, a vent connecting the interior of said bellows to atmospheric pressure, a casing enclosing the exterior of said bellows-operated valve, apipe connecting the space between said casing and said bellows to said condenser, adjustable spring means positioned within said bellows-operated valve acting upon said bellows to move said bellows toward a closed position, a second valve positioned in said lastmentioned pipe, a solenoid for operating said second valve," said solenoid being connected in series with said thermostatic switch and said steam pressure switch, and vent means to the atmosphere in said second valve, said second valve disconnecting said first-mentioned valve from said condenser when either said thermostatic switch or said steam pressure switch opens and connecting the space between said casing and said bellows to atmospheric pressure through said vent means.

JOHN D. STROBELL.

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